Fig. 2.

TU-BcX-4IC cells have an invasive, metastatic phenotype and are resistant to oncology drugs in vitro. Lungs and livers were harvested after serial passaging of TU-BCx-4IC in SCID/Beige mice (passages 1, 3 and 5 denoted T1, T3, T5). Organs were fixed, paraffin embedded, sectioned and stained with H & E to observe metastases. Quantification of lung metastases showed that area A of metastases per lung section were consistent over serial transplantation. Quantification of liver metastases showed that area B of metastases per liver section were also consistent over serial transplantation. C Peripheral blood was harvested from T3 passage of TU-BcX-49S and TU-BcX-4IC models. Human and mouse circulating cfDNA were detected in both PDX models. Although there was no difference between human cfDNA in the models, TU-BcX-49S had higher measurable levels of mouse-specific cfDNA. D TU-BcX-49S also exhibited higher levels of human circulating tumor cells compared to TU-BcX-4IC. Mouse DNA was utilized as the housekeeping gene in these experiments. E TU-BcX-4IC and MDA-MB-231 cells were embedded in Matrigel (0%, 20%, 40%) in 3D culture conditions. Representative images of embedded spheres were recorded after one and 3 days